Throttle locking device



Nov. 10, 1936 w A. SMITH. JR 2,060,256

' THR'QT LLLLLLLLLLLLLL CE II wil W7. mu/1 Jn IN VEN TOR Patented Nov.10, 1936 UNITED STATES THROTTLE L CKING DEVICE William A. Smith, Jr.,North Arlington, N. J., assignor to Worthington Pump and MachineryCorporation, New York, N. Y., a. corporation of Virginia ApplicationSeptember 27, 1934, Serial No. 745,675

1 Claim.

This invention relates to throttle valves for percussive tools such asrock drills and similar machines and. more particularly to a lockingdevice for holding such throttle valves of the rotary type in adjustedpositions.

An object of the invention is to provide a throttle valve locking devicewhich is wholly enclosed in the back head of a percussive tool, and onewhich, while being readily releasable, will hold the valve in adjustedpositions against accidental movement which might be caused by thejarring or vibration of the machine while in operation.

With these and other objects in view as may appear from the acompanyingspecification, the invention consists of various features ofconstruction and combination of parts, which will be first described inconnection with the accompanying drawing, showing a throttle lockingdevice of the preferred form, and the features forming the inventionwill be specifically pointed out in the claim.

In the drawing:

Fig. l is a section through the back head of a percussive tool showingthe improved locking device in place therein.

Fig. 2 is a cross section on the line 22 of Fig. 1.

Fig. 3 is a section taken on the line 3-3 of Fig. 1.

Referring more particularly to the drawing, I indicates the back head ofa percussive tool of any approved type, which is provided with a recess2 opening out through its rear end. The throttling valve-carrying plug 3extends into the recess 2 and has the stem 4 of the throttle valveconnected thereto for rotation with the plug 3. Any suitable type ofthrottle valve may be attached to the stem 4.

The plug 3 has a handle 5 formed thereon for facilitating its rotation.

A ratchet disc 6 engages against the inner end of the plug 2 and is heldfor rotation with the plug 2 by means of the projection I which engagesagainst the flat locking surface 8 of the ratchet disc 6. The ratchetdisc 6 has a plurality of radially extending notches 9 formed in itsinner surface which represents various adjusted positions of thethrottle valve. The projection I has a stop extension l0 formed thereonwhich co-operates with a stop shoulder II formed on the pawl-carryingmember I2 for limiting the rotation of the plug 3.

55 The pawl-carrying member I2 is inserted in the recess 2 in the backhead I and it is held against rotary movement by means of a key l3 whichfits in a slot I4 in the member I2.

The member I2 is provided with a transversely extending bore l5 whichreceives therein the locking pawl I6. The pawl I6 has a rectangular headI! which slides in the rectangular portion or channel I8 of the bore I5.The rectangular head I! engaging in the channel I8 prevents rotation ofthe pawl I6. The head ll of the pawl I6 and the notches 3 have inclinedco-operating surfaces as indicated at 26 in Fig. 3 of the drawing. Theincline or angle of the surfaces is such that the plug 3 will be heldagainst accidental rotation which might be caused by the vibration setup during the operation of the tool; however, they are such that theapplication of rotating force to the plug 3 will cause the ratchet disctoslide over the inclined surfaces 20 of the head I! and depress thepawl in the bore I6 against the tension of its spring 2|.

From the foregoing description taken in connection with the accompanyingdrawing it will be seen that an eiiective locking or latching mechanismis provided which will prevent accidental adjustment of the throttlevalve (not shown) carried by the stem 4 and one which will, however,permit adjustment of the throttle valve by manual rotation of the plug 3without requiring manual release of the latching pawl.

It will be understood that the invention is not to be limited to thespecific construction or arrangement of parts shown but that they may bewidely modified within the invention defined by the claim.

What is claimed is:

In a locking device for percussive tool throttle valves, a throttlevalve stem, a back head having a recess therein, a rotatable back headplug extending into said recess, said stem attached to said plug, aratchet disc in said recess and having a plurality of radial ratchetnotches therein, a fiat locking surface on one side of said ratchetdisc, a projection on said back head plug engaging said fiat surface andconnecting said disc to said plug for rotation therein, a lockingpawlcarrying member in said recess, a locking pawl carried by saidmember and attached to engage in said radial ratchet notches, a keycarried by said back head and engaging said locking pawl-carrying memberto prevent rotation thereof, a spring for urging said pawl into any oneof said notches, a stop shoulder formed on said pawl-car rying memberand an extension formed on said back head plug for engagement with saidstop shoulder to limit rotation of the plug.

WILLIAM A. SMITH, JR.

